Recent frigid temperatures (and moisture) have been a blessing. With the warm temperatures in January, buds had begun to swell early and sugars were becoming active in the still-dormant wood.

Early bud break in Lubbock makes buds vulnerable to late spring freezes, and gardeners depend on buds remaining dormant until all danger of frost is past to harvest a summer fruit crop.

While buds are still dormant is the opportune time to treat fruit trees for scale pests. Horticultural oils, oil used to control pests on plants, are among the safest treatments. Summer or foliar oils are used on plants when foliage is present; dormant oils when tissue is dormant.

Dormant oil is a safe preventive for overwintering pests like scale if sprayed while buds are dormant before opening and are effective if they come in contact with the insect. Therefore, apply in the winter months when the insects are sessile (stationary). The petroleum-based oils dissolve the protective waxy coatings of pest eggs. Thoroughly coat when the fruit tree is dry and never apply when below freezing.

Dormant oils generally are not harmful to beneficial insects as those populations aren’t around that time of year. Dormant oils have low toxicity to humans and pets. Dormant oils lose the ability to control pests once dried, and can harm plants susceptible to oil sprays, such as cedars, maples, spruce and junipers.

Armored and soft scales are the most common groups targeted by dormant applications of oil. Females may look like protuberances of wood. Armored scales have bodies that are under covers (shells) that have a slight nipple with concentric rings.

The females’ eggs are hidden under their shell and hatch into tiny crawlers that walk over plant surfaces; crawlers are blown by wind to other plants or carried by humans or wildlife and begin feeding almost immediately.

Females spend their entire life feeding at the same spot. Scale insects can be serious pests on perennials, but not all cause harm; thus, identify your insect.

Scales do damage by inserting their proboscis (tiny, straw-like mouthpart) into the plant tissue that transports sugars around the plant and feed on bark, fruit or leaves.

Q&A

A-J reader P.G. asks about pruning plum trees. Plums are trained similarly to pears, in that scaffold branches are selected and separated by at least 6 inches. They are pruned similar to peaches. As trees mature and dense growth increases, thin-out smaller diameter wood.

Since mature plum trees bear fruit on spurs, vegetative growth can be removed, thereby opening up the canopy to sunlight, which will enhance plum production.

ELLEN PEFFLEY TAUGHT HORTICULTURE AT THE COLLEGE LEVEL FOR 28 YEARS, 25 OF THOSE AT TEXAS TECH, DURING WHICH TIME SHE DEVELOPED TWO ONION VARIETIES. SHE IS NOW THE SOLE PROPRIETOR OF FROM THE GARDEN, A MARKET GARDEN FARMETTE. YOU CAN EMAIL HER AT GARDENS@SUDDENLINK.NET.